Peloroplites

In 2001, a skeleton of a large nodosaurid from the Cedar Mountain Formation in Emery County, Utah was mentioned by Burge and Bird in a publication about the faunal composition of the Price River II quarry. More material was obtained and was subsequently described in 2008 by Kenneth Carpenter, Jeff Bartlett, John Bird and Reese Barrick. The Price River II quarry was previously reported as occurring in the Ruby Ranch Member by Burge and Bird (2001) but was later reported as occurring in the base of the Mussentuchit Member due to the dark, carbonaceous nature of mudstones of the strata. The Price River II quarry has also produced specimens pertaining to four individuals of a new brachiosaurid, an iguanodontid, associated cranial and postcranial material of Cedarpelta, a turtle and a pterosaur. The holotype specimen, CEUM 26331, consists of a partial skull. Additional specimens were assigned to Peloroplites that consist of cervical vertebrae, dorsal vertebrae, synsacrums, caudal vertebrae, chevron, scapula-coracoids, humeri, radii, ulnae, ilia, pubis, ischium, femora, tibiae, fibulae, metacarpals, metatarsal, metapodials, phalanges, unguals, osteoderms and various bone fragments. The holotype and assigned specimens are currently housed at the College of Eastern Utah, Prehistoric Museum, Utah. The generic name, Peloroplites, is derived from the Greek words "peloros" (monstrous, gigantic) and "hoplites" (heavily armed), and as a subjunctive, a heavily armed soldier. The specific name, cedrimontanus, is derived from the Latin words "cedrus" (Cedar) and "mont-" (mountain), in reference to the Cedar Mountain Formation. Carpenter et al. (2008) suggested that some of the large nodosaurid material from the Ruby Ranch Member of the Cedar Mountain Formation that has been questionably identified as Sauropelta may actually belong to Peloroplites. If the material does belong to Peloroplites, then it would extend the stratigraphic range based on a specimen described by Warren and Carpenter (2004). However, one specimen tentatively referred to Sauropelta cannot be assigned to either that genus or to Peloroplites. The specimen was obtained from the Poison Strip Sandstone Member of the Cedar Mountain Formation and assigned to Hoplitosaurus by Bodily (1969) based on the morphology of the spines. The compressed, triangular spines of the specimen are characteristic of polacanthines, which also includes Hoplitosaurus. Carpenter et al. (2008) considered that the specimen probably represents an unnamed large polacanthine. ==Description==

Size and distinguishing traits Carpenter et al. (2008) originally gave Peloroplites an estimated length of 5-5.5 metres (16-18 feet). A right ilium and left pubis represent the only material of the pelvis. The preacetabular process of the pelvis diverges 55° unlike Sauropelta where it diverges 39° and 28° in Edmontonia. However, the degree of divergence might possibly be an artefact of not having a complete medial surface. The postacetabular process is broad and short. Additionally, the lateral surface is almost straight rather than concave. The pubis is robust and has a lateral face that forms the anterior wall of the acetabulum. The preacetabular process is short, straight and thick, while the postpubic process is short and angled posteroventrally. Both the left and right femora are complete and are relatively straight shafted. The head of the femora are set at a slight upward angle. The left femur preserves an oblique transverse ridge that is present below the greater trochanter but is damaged and better seen on the right femur. The cnemial crest of the tibia is short and rounded in profile. The tibial shaft is thick throughout its length and astragalus is not fused to the distal end of the tibia. Only a right metatarsal and ungual are known of the hindfoot. The metatarsal is proportionally shorter and more robust than the metacarpals of the manus. As in Sauropelta, the proximal end of the metatarsal is sloped laterally in anterior view and the distal condyles are well developed. The ungual is broad throughout its length. ==Phylogeny==

Carpenter et al. (2008) originally placed Peloroplites within Nodosauridae but did not conduct a phylogenetic analysis to determine its exact relationships within the clade. However, Yang et al. (2013) found Peloroplites to be sister taxon to both Taohelong and Polacanthus, while Zheng et al. (2018) found it to be sister taxon to Taohelong and a large clade containing more nested taxa such as Nodosaurus, Edmontonia, Struthiosaurus and Europelta. Rivera-Sylva et al. (2018) placed Peloroplites as sister taxon to Sauropelta, Taohelong and a clade containing more nested taxa. A phylogenetic analysis conducted by Rivera-Sylva et al. (2018) and modified by Madzia et al. (2021) is reproduced below. }} The results of an earlier analysis by Thompson et al. (2012) are reproduced below. }} ==Paleobiology==

Peloroplites is known from the uppermost part of the Cedar Mountain Formation, a layer known as the Mussentuchit Member. The layer was originally interpreted as being of Aptian to Albian age (~109–116 Ma) using radiometric dating. The Mussentuchit Member has been interpreted as a either a wet, lacustrine environment or a fluvial environment like a distal delta system at the western margin of the Western Interior Seaway. the brachiosaurid sauropod Abydosaurus, the tyrannosauroid Moros, the carcharodontosaurian Siats, the indeterminate coelurosaur Richardoestesia, the ankylosaurs Animantarx and Cedarpelta, an indeterminate neoceratopsian, cf. Bernissartia the snake Coniophis, the amphibian Albanerpeton, the turtles Glyptops and Naomichelys, the mammals Astroconodon, Spalacotherium, Symmetrodontoides, Paracimexomys and Kokopellia, the batoids Ischyrhiza and cf. Baibisha, the hybodonts Polyacrodus, Lissodus and Hybodus, and the lungfish Ceratodus. ==References==